The present invention relates to an external operation handle device used in circuit breakers, for example, a molded case circuit breaker, an earth leakage breaker, and the like.
An external operation handle device, an accessory device for a molded case circuit breaker, an earth leakage breaker, and the like, is known (for example, Patent Document 1: Japanese Unexamined Patent Application Publication No. 2005-149918), which operates a circuit breaker disposed inside a switch board, a control board, or the like, for open and close operations of the circuit breaker from outside of the board.
The external operation handle device has a rotary handle and a drive mechanism mounted on a mounting base, the drive mechanism linking the rotary handle and a locker handle of the circuit breaker. The external operation handle device assembled with the circuit breaker disposed inside the board is operated by rotating the rotary handle from outside the board to drive the rotary handle of the circuit breaker to ON or OFF position.
A type of an external operation handle device having a door lock mechanism is known (for example, Patent Document 2: Japanese Unexamined Patent Application Publication No. H5-67423), in which an interlock mechanism is provided between the rotary handle and the door panel of the board to lock the door panel at a closed position in normal conditions, preventing the door from being opened accidentally.
Another type of an external operation handle device having a handle lock mechanism is known (for example, Patent Document 3: Japanese Unexamined Patent Application Publication No. 2002-25411), in which a pull-out type handle lock lever is provided at the rotary handle of the external operation handle device and pulled out at the OFF position (or ON position) to hang a padlock on the pulled out hand lock lever and lock the rotary handle at this position.
FIGS. 7 and 8 show a prior art structure of an external operation handle device with a door lock mechanism and a handle lock mechanism. In these drawings, the reference numeral 1 designates a circuit breaker, and the reference numeral 2 designates an external operation handle device disposed on the front surface of the circuit breaker 1. The circuit breaker 1 has functional parts disposed in a main housing 1a, including a fixed contact 1b, a movable contact 1c, a switching mechanism 1d of a toggle link type, a rotary handle 1e disposed at the top of the main housing 1a, and an over-current tripping device 1f. 
An open-and-close operation of the circuit breaker 1 is well known. As a result of turning the rotary handle 1e from the ON position shown in FIG. 7 to the OFF position in the right, a toggle linkage of the switching mechanism 1d reverses, and the movable contact 1c receives an urging force from a switching spring and opens. When an over-current runs in the main circuit and the over-current trip device 1f works, the switching mechanism 1d trips. As a result, the switching mechanism 1d opens the movable contact 1c and interrupts the current automatically. In this trip operation, the rotary handle 1e moves according to the toggle link motion of the switching mechanism 1d to an intermediate position between the ON and OFF positions and stops at that position.
The external operation handle device 2 has, as described in detail in Patent Document 1, a rotary handle 4, a drive mechanism combining a turn base 5 and a slide base 6, and a handle cover 7 mounted on a mounting base 3.
The turn base (a crank arm) 5 of the external operation handle device 2 is connected to a shaft of the rotary handle 4 directly or through a latch. The slide base 6 is combined with the back surface of the mounting base 3, and guided and supported slidably in the open-and-close direction of the rotary handle 1e of the circuit breaker. In the central region of the plate of the slide base 6, an oblong hole is opened in the direction perpendicular to the sliding direction and engaged with a pin (a crank pin) 5a provided on the turn base 5 to link with the rotary handle 4. The slide base 6 has handle arms 6a, which are protrusions sandwiching the grip of the rotary handle 1e between the front and back sides. The rotary handle 1e is put between and engaged with the handle arms 6a in the installed state in the circuit breaker 1 (see FIG. 7). The handle cover 7 has a name plate 7a attached on the top surface thereof to indicate the positions (ON, TRIP, OFF, and OPEN) of the rotary handle 4.
In operation, turning the rotary handle 4 to an ON or OFF position, the rotational motion is converted into a linear motion through the turn base 5 and the slide base 6. Accordingly, the rotary handle 1e of the circuit breaker 1 is driven through the handle arms 6a of the slide base 6 to the ON or OFF position to close or open the main circuit contact points.
The external operation handle device 2 is equipped with a pull-out type handle lock lever 8 that is a handle lock device to lock the rotary handle 4 at an OFF position (or ON position), and a door lock lever 9 that is an interlock device with the board door.
FIG. 9 is an exploded perspective view showing the interlock between the external operation handle device 2 mounted on a circuit breaker 1 and a door panel of a switch board or the like. In FIG. 9, the reference numeral 10 designates a door panel of the switch board. The reference numeral 11 designates a decorative sheet attached on the front surface of the panel adjusting to a handle hole 10a opened in the door panel 10. The reference numeral 12a designates a latch formed at the inner periphery of a latch plate 12. The interlock is performed by engaging this latch 12a with a door lack lever 9 provided on the external operation handle device 2 to lock the door panel 10 at a closed position.
Next, a description is made as to a detailed structure and operation of the door lock mechanism with reference to FIG. 10. The door lock lever 9 is protruding sideward from a location between the handle cover 7 and the mounting base 3 of the external operation handle device 2 so as to oppose the latch 12a shown in FIG. 9. The door lock lever 9 is pivotally supported by a shaft (a release pin) 9a in the back surface side of the handle cover 7 as shown in FIG. 10. A cam portion of the door lock lever 9 projects to the path of movement of the protrusion 5b of the turn base 5 that is connected to the shaft 4a of the rotary handle 4. Below the door lock lever 9, a leaf spring 13 is provided to include a ridge portion for cramping and holding the door lock lever 9 at a locked or unlocked position.
The above-mentioned Patent Document 2 describes in detail the lock and unlock operations of the door panel 10 by the door lock lever 9. The door lock lever 9 normally stays at the position indicated by the two-dot chain line in FIG. 10 and is engaged with the latch 12a of the door panel so that the door panel 10 shown in FIG. 9 does not open and is locked at the closed position. To open the door panel 10 from this state, the rotary handle 4 is first turned to an OFF position (FIG. 8) to open the circuit breaker 1, then the rotary handle 4 is turned from this OFF position further to an OPEN position. As a result, the turn base 5 in FIG. 10 turns counterclockwise, and the protrusion 5b of the turn base 5 pushes the cam portion of the door lock lever 9. Accordingly, the door lock lever 9 swings clockwise about the shaft 9a and is released from the latch 12a. At the same time, the door lock lever 9 comes over passing the ridge 13a formed in the leaf spring 13 and held by itself at the unlocked position. At this position, interlock with the door panel 10 is released allowing the door to be freely opened.
When the rotary handle 4 is once manipulated to turn to the OPEN position and then released, the rotary handle 4 returns to the OFF position. When the opened door panel 10 is closed, a return tab (not shown), provided on the latch plate 12 in FIG. 9 and opposing the latch 12a, collides with the bottom edge of the door lock lever 9, pushing the lock lever back to the lock position. As a result, the door lock lever 9 comes over passing the ridge 13a of the leaf spring 13 and holds by itself at the lock position.
Another method for return operation of the door lock lever 9 is known (Patent Document 4: Japanese Unexamined Patent Application Publication No. H9-312119, for example), in which two mounting seats for the leaf spring 13 are provided and one of the seats for the leaf spring 13 is selected to change between a manual return and an automatic return.
Patent Document 3 describes in detail the function and operation of the handle lock lever 8 provided in the external operation handle device 2 of FIG. 8. At the position where the rotary handle 4 turned to the OFF (or ON) position, referring to FIGS. 11(a) and 11(b), a finger is put on the handle lock lever 8 and the handle lock lever 8 is pulled out towards the periphery of the rotary handle 4 (in the direction of the arrow in FIG. 11(b)), and after that, a padlock 14 is hung on the handle lock lever 8 to lock the rotary handle 4 at this position.
The external operation handle device having the conventional structure as described above, however, has the following problems about operation and performance of the door panel lock mechanism and handle lock mechanism thereof.
As described referring to FIG. 10, in order to hold the door lock lever 9, which is unlocked by turning the rotary handle 4 to the OPEN position, at the unlock position by itself, a ridge portion 13a of the leaf spring 13 is used in the conventional structure, the ridge portion being disposed opposing the cam portion of the door lock lever 9. In this arrangement, however, a range of adjustment is narrow for the door lock lever 9 to hold by itself at the lock/unlock position and readily affected by the configuration and dimensional accuracy of the leaf spring 13. Consequently, it may become unstable to hold the door panel by itself at the lock/unlock position due to deformation of the leaf spring 13 during a long term operation. In addition, adjustment between the door lock lever 9 and the latch 12a provided at the board side is delicately affected. Therefore, it takes a long time and efforts in the adjustment work at the job site in which the circuit breaker 1 is installed in a switch board to correctly set a relative position between the door lock lever 9 of the external operation handle device 2 and the latch plate 12 attached to the door panel 10 (FIG. 9). A solution for this problem is eagerly demanded by the users.
As for the handle lock lever 8 provided on the rotary handle 4, it is troublesome to put a finger on the lock lever 8, and pull out and push in whenever the lock and unlock operation is conducted.
The present invention has been made in view of the above problems, and an object of the invention is to solve the above problems and provide an external operation handle device with improvement in that a simple push operation can carry out interchange between pulling out and returning back of the handle lock lever, and the handle lock function of the handle lock lever is smartly utilized in lock/unlock operation of the door lock lever that performs interlock with the door panel of a switch board.
Further objects and advantages of the invention will be apparent from the following description of the invention.